Thanks, @Onion. I saw this post as I was almost asleep and didn’t want to trudge back downstairs and get the mind going when I needed to be up early.
I’ll give you some advice from my experiences. It’s important to realize that the who, what, and why of Shadow People will vary based on those people’s experiences with them and their own personal knowledge. Velenos and I would not agree in this area, but both of us have effectively dealt with them in different ways, with different means, and (I’m assuming with this one) for different purposes.
That said, banishing and/or petitioning a Deity (or similar) are the easiest means. If you only come across on here or there, this may be the route you should think about.
If you’re coming across them more frequently than that or you’re attracting the stronger ones, it may be time for shadow work, which is what Onion’s approach is better geared towards. I took this approach when I found one in my bedroom. Frankly, I didn’t really believe in them until then and had figured they were just people’s inability to discern some other entity or one masking as a shadow for the sake of Fear. Joke was on me.
In my Shadownomicon work through, I had various means of dealing with them, but the point of the book is integration of those aspects they would feed on. It was through interacting with the archetypes in the Shadownomicon that I was also interacting with my own, despite years of counseling and genuine hard work in this area.
I also cultivated the relationship with the hive I was interacting with and have used them for other means. This is possible when you’re not a food source for them anymore, but I would suggest not going down this route if you’re a newer magician (I don’t know if you are or aren’t). To get the most out of that book and any possible relationship, you need your clairs opened enough for consistent communication at the least and the ability to claim sovereignty over your space, as @Veil’s entry speaks of.
You can read about my experiences as I worked through the book here. I left up all of my mistakes, frustrations, incorrect methods I tried, etc… Lots of struggles with that, as any shadow work should contain them. Half of it is Abaddon and Co. inserting lessons into it when they felt the time was appropriate, but I captured them as reported it with it, since it was related.
Hope this helps.